You will need

Your Tails

1 other TailsDVD or USB

As it is currently impossible to install Tails directly from
Windows,Linux,macOS,
this scenario requires creating an intermediary Tails on a second USB stick.
This intermediary Tails lacks important security and usability features.

1 USB stick8 GB minimumAll data will be lost!

It is currently impossible to manually upgrade a Tails USB stick
while running from itself. This scenario requires creating an
intermediary Tails on another USB stick, from which to upgrade your
Tails.